The present invention relates to a junction box particularly for lighting lines for tunnels.
As is known, in tunnels, lighting is ensured by a plurality of lamps arranged along the route and powered by means of a power supply line.
At the position of each lamp, the power supply line is interrupted by a junction box, in which a terminal strip connects the power supply wires to a socket for the lamp.
The junction box is provided with a degree of protection that ensures a certain resistance to water and dust.
Conventional junction boxes have drawbacks from the point of view of installation and maintenance.
The installation of a conventional junction box in fact entails cutting the wires of power supply line in order to connect them to the terminal strip.
The operations of cutting and connecting the wires, the application of the gaskets and the closure of the box are time-consuming and laborious, also considering that they are performed in an elevated position by an operator who stands on a trestle.
The junction boxes normally used in tunnels also have a severe drawback from the point of view of safety, because in case of fire they do not ensure continuity of the power supply on the entire line.
That is due essentially to the structure of the terminal strip, which in case of high temperatures melts, causing a short circuit.
In other words, not only is lighting lost in the region of the fire, where of course the lamps are destroyed, but power fails along the entire line and therefore also to the lamps that are distant from the point of the fire.
The shutoff of all the lamps in a tunnel entails that even people who are far from the point that is directly affected by the fire are unable to find the exit.